Multicylinder motor or engine with double-acting pistons

ABSTRACT

An internal-combustion engine or fluid (pneumatic or hydraulic) motor has a fixed central shaft formed with a sun gear, and a housing rotatable around the shaft. This housing is formed with a plurality of bores each subdivided into two compression chambers by a double-acting piston which is displaceable along an axis parallel or transverse to the shaft axis. Each piston is connected by a crank to a pinion which acts as a planet gear meshing with the sun gear so that reciprocation of the piston causes the planet gear to rotate, thereby entraining the housing about the fixed shaft. Alternatively the device may be driven mechanically to operate it as a pump.

United States Patent 1191 COOLANT Von Esch July 16,1974

[ MULTICYLINDER MOTOR 0R ENGINE 2,432,426 12/1947 WITH DOUBLE-ACTING PISTONS [75] Inventor: Paul Von Esch, Zurich, Switzerland 2:990: 20 7 19 1 [73] Assignee: Bekama AG, Zug, Switzerland 343l'894 3/1969 [22] Filed: Apr. 17, 1972 Primary Examiner---Ca J. Husar 21 pp NO: 141101718), Agent, 0! ROSS; Herbert Dubno [30] Foreign Application Priority Data [57] ABSTRACT Nov. 18, 1971 Switzerland l692l/7l An intemabcombustion engine or fluid (pneumatic or hydraulic): motor has a fixed central shaft formed with [52] 123/43 23/44 2 7 a sun gear, and a housing rotatable around the shaft. I Int Cl F02br57/00 This housing is formed with a plurality of bores each [58] Fieid 417 subdivided into two compression chambers by a dou- 91/472 ble-acting piston which is displaceable along an axis 7 parallel or transverse to the shaft axis.v Each piston is connected by a crankto a pinion which acts as a [56] References Cited planet gear meshing with the sun gear so that recipro- UNITED STATES PATENTS cation of the piston causes the planet gear to rotate, l,242,l97 10/1917 Johnson 123/43 R thereby entraining the housing about the fixed shaft. 13411332 5/ 1920 McDonald l23/43 R Alternativelythe device may be driven mechanically 1,380,404 6/1921 Miller 123 43 R to Operate it a pump 2,244,438 6/l94l Wilkerson 123/43 R ll/l943 Talbot 123/43 R.

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EXHAUST MULTICYLINDER MOTOR OR ENGINE WITH DOUBLE-ACTING PISTONS FIELD or THE INVENTION BACKGROUND OF THE INVENTION tain, although the axes of the cylinders lie in a common 7 plane perpendicular to the shaft axis.

Various rotary-piston machines have also been suggested to take advantage of the use of each piston as a wall ofa leading chamber and trailing chamber. Problems of sealing the annular chamber against the pistons and the rotating shaft have been encountered.

While the systems described sketchily above are internal-combustion engines, similar systems have been used without ignition of a fuel/air mixture when the power fluid is an expanding gas, a liquid under pressure or the like. These machines are hereinafter designated as fluid motors and have a rotatable element connected to a load as in the case of an internalcombustion engine. Of course, when the machineis driven by an expanding fluid derived from an external combustion chamber, the system may be denominated an external-combustion machine." Also, fluid machines include pumps wherein the rotating element is driven by some other motor or prime mover and the pistons apply pressure to a fluid.

OBJECTS OF THE INVENTION It is an object of the present invention to provide an improved multiple-cylinder machine which can be used as an internal-combustion engine, a fluid-powered motor, pump or the like.

Another object is the provision of such a multipiston machine which avoids the disadvantages of the priorart systems mentioned earlier.

Yet another objectis the provision of an improved internal-combustion engine wherein power is delivered especially uniformly to the output or drive shaft.

SUMMARY OF THE INVENTION fixed gear is a ring gear (and supplants to the sun gear), or the housing is fixed while the sun or ring gear is rotated.

The cylinders and their pistons have axes which lie parallel to the rotation axis of the motor or engine or spaced from and at right angles to this axis. When the device is used as an' internal-combustion engine the central body or shaft is advantageously fixed and formed with axially extending intake and exhaust passages having radially opening orifices which register with holes in the housing'for operation of the engine.

From the foregoing, it will be apparent that the system of the present invention differs from multipiston machines of conventional construction in that, while a cylinder is provided individually for each piston and there is no common chamberorbited by the pistons, each piston may be double-acting in the sense that the oppositesides of the piston are alternately subjected to the expansion force to drive the rotating member of the assembly. I

Preferably, the pistons and the associated cylinders are angularly equispaced about the axis of rotation and the stationary shaft. When the axes of the cylinders are parallel to the shaft axis and the axis of rotation of the rotatable member of the machine, the cylinders may be wholly confined between a pair of parallel planes perpendicular to-the shaft and rotation axes. When, however, the cylinder axes are generally transverse to the shaft and rotation axes, I prefer to provide the cylinders in parallel-cylinder pairs, the cylinders of each pair being-disposed symmetrically with respect to an axial plane through the system. When two or more such pairs are provided, I have found it to be advantageous to provide allof the pairs in a single plane perpendicular to the shaft and rotation axes or in a pair of axially spaced parallel planes which are perpendicular to the shaft and rotation axes.

According to an important feature of the present invention, the central shaft is provided with duct means and ports registering with the cylinders for delivering and/or removing the power fluid from the working compartments of the cylinders on opposite sides of the respective pistons. The power fluid may be a combustible fuel/air mixture when the machine is operated as an internal combustion engine, or a vaporizable fluid or a fluid under pressurewhen the machine is a fluid machine as defined above. When the apparatus is operated as an internal combustion engine, the duct system provided in the shaft allows the housing to be formed with cooling ribs or fins which increase the het exchange with the surrounding air as the housing rotates.

The shaft is preferably provided with passages for a liquid coolant which may be circulated by the enginecooling pump through the shaft and a radiator connected in circuit therewith.

The internal combustion engine may be operated as a four-stroke engine or a two-stroke engine in accordance with gasoline-engine principles generally. In the latter case it has been found to be advantageous to provide a feed pump for charging a fuel/air mixture into the cylinders.

Of course, when the machine is operated as a hydraulic or pneumatic motor or pump, the shaft orbited by the housing may be provided with distributing or valving ports, slots or channels which eliminate the need for other valve structures.

It has been found to be advantageous to provide the double-acting pistons with keying means for preventing rotation of the pistons about their respective axes, e.g.,

in the form of a longitudinal piston groove along the periphery, and a formation projecting from the cylinder wall into this group. A roller arrangement may be provided between this formation and the groove wall to reduce frictional engagement while preventing play.

According to still another feature of the present invention, the cylinders, although receiving independent pistons, may be interconnected or provided with fuel or other channels common to two or more such pistons. With the gear arrangement mentioned earlier, it is possible to operate the pistons of two adjoining and interconnected cylinders so that the pistons move generally away from one another or toward one another synchronously in the expansion and compression strokes respectively. For'the most part, the cylinder bores and pistons are so constructed and arranged as to distribute the forces uniformly on opposite sides of the shaft axis thereby minimizing stress and vibration.

DESCRIPTION OF THE DRAWING The above and other objects, features, and advantages will become more readily apparent from the following description, reference being made to the accompanying drawing in which:

FIGS. 1-3 are diagrammatic perspective views showing cylinder layouts for engines representing three embodiments of the present invention;

FIG. 4 is an axial section through an eight-cylinder machine with a cylinder layout similar to FIG. 1;

FIG. 5 is an end view, partly broken away and in section 1 of the engine of FIGS. 1 and 4;

FIG. 6 is a section taken along line VI-VI of FIG. 5;

FIG. 7 is a detail of FIG. 6 in enlarged scale;

FIG. 8 is a schematic diagram illustrating the operating cycle of the engine of FIGS. 1 and 4-7;

FIGS. 9 and 10 are views corresponding to FIGS. 4 and 5, respectively, showing the embodiment of the present invention partially illustrated in FIG. 2;

FIG. 11 is a view similar to FIG. 9 showing the embodiment of the invention seen in FIG. 3;

FIGS. 12, 13 and 14 are, respectively, top, top axial sectional, and side views of a piston usable in the present invention;

FIG. 15 is a section taken along line XV-XV of FIG. 13;

FIG. 16 is a cross section through an embodiment of the present invention similar to that of FIGS. 1 and 4-8 (and using the piston type of FIGS. 12-15);

FIG. 17 is a sectional view showing the carburetion and exhaust system of the embodiment of FIG. 16;

FIG. 18 is a schematic diagram similar to FIG. 8 showing four-cycle operation of the engine of FIGS. 16-17; and

FIG. 19 is a diagram similar to FIG. 18 illustrating two-cycle operation of the engine of FIGS. 16-17.

SPECIFIC DESCRIPTION F IG. 1 shows a basically cruciform housing or rotor G rotatable about a fixed shaft 3 and formed with cylinder bores 1 extending through the arms of the rotor at right angles to and spaced from the rotation axis A. Secondary bores 2 cross the cylinder bores 1 and, as described below, serve to receive the cranks.

More specifically, as seen in FIGS. 4-8 an eightcylinder motor has a cylinder housing 10 formed with four cylinder bores 29 (1) and foursecondary bores 12 (2) destined to receive the cranks. The housing is provided with external cooling ribs 13 and with a jacket 11 for guiding cooling air overthese ribs. Four cylinder heads 28 give the cruciform housing 10 a circular shape. The housing 10 is connected to a bearing housing 14 constituting effectively a planetary-gear carrier as will be seen below. The half 14 of the housing is rotationally linked by means of a flange 15 to an output shaft 16 that constitutes the motor drive shaft.

The housing 10 is also covered by a disk 17 which is formed with external gear teeth 18 adapted to be engaged'by a starting motor (not shown) and which rides via a bearing 45 on the shaft 19. The bodies 10, 14, 15, 17, and 28 are interconnected by bolts and rotatable as a unit about a fixed axial shaft 19 (3) which itself is supported on a fixed support plate 20. A sun gear 21 is provided on the end of the shaft 19 away from the support 20 and is also nonrotatable with respect to axis A.

The engine is provided with a carburetor 22, a pair of exhaust pipe 23, a spark-distribution ring 24 fixed on the axis 19, a set of points 25, a pair of ignition coils 26, and spark plugs 27 passing through the disk 17. The housing 10 is formed with four pairs of holes 30 which open tangentially in opposite directions into one of the four cylinder bores 29. The holes 30 open on the inner periphery of the housing 10 next to each other. The points 25, which operate bothignition coils 26, are operated by a cam 46 which is carried on a shaft 47 connected to the output shaft 16 and passing axially through the center of the motor and supported in the fixed plate 20 by a ball bearing 48. The carburetor 22 is of the conventional type operated by an accelerator.

Each piston 31 is sealed by means of rings 31a in its respective bore 29 and forms therein a pair of compression chambers 29a and 29b. A short crankshaft 34 rotatable in the bore 12 transverse to the bore 29 has a crank 33 engaging in a cutout 32 formed with a trans verse groove 35 in the side of the piston 31, as seen in FIG. 6. This groove 35 is U-shaped in cross section and extends at right angles to the pistons displacement axis A. A two-part hardened lining 36 is provided in the groove 35 in which two needle-bearing mounted rollers 37 ride. The lining 36 is slightly stepped so that it has one surface 36' (see FIG. 7) in constant contact on one side with one roller 37 and another surface 36" on the other side in contact with the other roller for constant contact free from play. An axial groove 38 is formed in the opposite side of the piston and is similarly provided with a hardened lining 40 that receives a roller 39 mounted on the housing 10 and held in place by disk 17 to prevent rotation of the piston 31 in its bore 29. Of course the roller 38 could be doubled and used with a stepped lininglike the rollers 3, if desired.

The crankshaft 34 is carried in roller bearings 41 and 42 in the housings 10 and 14. A spur-gear pinion 43 is keyed to the shaft 34 and is formed with a counterweight 44 opposite the crank 33. Each pinion 43 meshes with the sun gear 21 and has one quarter as many spur-gear teeth as this sun gear so that it must rotate four times for each single revolution of the output shaft 16.

It ispossible to power the engine with a gas-oil mixture in order to provide for lubrication of its various pump 50 to bleed excess oil back into the reservoir R.

Cooling water is circulated through longitudinal holes 54 in the shaft 19. This coolant is fed in by a pump 54a through a ring 55 formed in the plate 20, then passes axially in bores 54 in one direction through the shaft to its end where it is reversed by a rubber gland 56 and flows axially back in the other direction for collection in a groove 57 formed in the plate 20 within the circular groove 55.

Air is drawn into the engine through a pair of diametric'ally opposite and axially extending intake channels 58 in the shaft 19 which are formed with radially opening orifices 58a. Exhaust is expelled by diametrically opposite and axially extending exhaust passages 59 opening at respective orifices 59a. The exhaust passages 59 are offset by 90 to the intake passages 58.

FIG. 8 shows the operation of the motor. The control orifices 58a and 59a of the fixed shaft 19 are shown respectively dotted and cross-hatched. The entire surface of the shaft 19 and the four cylinders are shown in a planar arrangement although actually they are arrayed around the axis A. It can be seen that the entire 360 rotation of the housing is divided into eight regions l/2 U, with U being equal to one full 360 rotation of a crank 34. Thus for each rotation of the housing 10 each crank will turn four times, thereby causing each piston 31 to perform two'compression strokes and two power strokes. This gives a total of eight power strokes for each rotation of the shaft 16, so that an extremely uniform torque is applied to this shaft 16, twice times as many power strokes taking place for each output shaft revolution as in conventional eight-cylinder motors.

The arrows show the relative directions of the shaft 19 and the housing 10. So it can be seen how one set of holes 30 will pass through overlapping intake and exhaust regions, then a region where they are closed during which ignition and the power stroke takes place, and finally into another such cycle for two complete Otto cycles per revolution of housing 10. Two oppositely directed tangential holes 30 are provided in conjunction with slightly overlapping intake and exhaust orifices 58a and 59a in order that good scavenging of the useless exhaust gases with clean air will take place for best efficiency. Since the motor is so arranged that ignition will always take place in diametrically opposite cylinders, the amount of wear on bearing-45 is greatly reduced and avery tight fit of the housing 10 on the shaft 19 is possible, with the circumferential grooves 53a helping to seal between the shaft 19 and housing 10.

One such engine haseight cylinders each with 25 cubic centimeters of displacement to give a total displacement of 200 cc. The bore is 41.5 millimeters and the stroke 20 millimeters. Thus when the output shaft 16 rotates at 3,000 revolutions per minute, the small cranks turn at four times this rate, or l2',000 rpm. This crank rotation rate appears high, but since the stroke is only 20 millimeters, the piston speed is only around 8 meters per second, which is entirely within nonnal machine capacities. The engine exhibited minimal throw, and generated only a hum, more reminiscent of an electric motor than an intemal-combustion engine.

It should be noted that if fluid under pressure is supplied to the engine of FIGS. 1 and 4-8 in the channel 52 by, for example, a pump 52a this engine will become a highly efficient hydraulic motor. Any fluid medium such as air or hydraulic fluid may be used, in which case the carburetion and ignition systems may be dispensed with.

Similarly if the intake channel 58 is connected to a source of fluid and the shaft 16 is rotated, the device will function as a pump. Of course the housing 10 can be fixed and the shaft 19 driven, to reverse the operation of the machine. I

In FIGS. 2, 9, and 10 the rotor comprises a pair of mutually orthogonal housings G and G carried on the shaft 3 and each formed with two cylinder bores 1 both defining a plane orthogonal to the motor axis A and extending transverse to the shaft 3 and with two crank bores 2 extending parallel thereto.

With particular reference to'FIGS. 9 and 10 (Note that in FIG. 9 the two rotor halves are shown to be parallel to each other, for purposes of illustration.) each housing (G and 101 (G has four cylinders 129 (1) defined by pistons 131. A sungear 102 is formed between housings 100- and 101 on the shaft 107 and is engaged by the pinion planet gears 134 of the crankshafts 103. These crankshafts 103 are set in bearings 141 in theirrespective housings and in bearings 110 seated in the cylinder head 104 of the opposite housing. The control orifices 109 in the shaft 107 are offset at 22.5 intervals.

Th principal advantage to the embodiment shown in FIGS. 2 and 9 and 10 is that the cylinder heads 104' have flat, planar surfaces that can be very securely bolted to the respective housings. At the same time very. heavily ribbed cylinder heads 104 can be used for most efficient heat dissipation. Another one or two housings can be mounted on the same shaft in a similar manner to, produce a 12 orl6-cylind er engine.

The spark plugs 105 extend axially from the cylinder heads 104. Only one of the spark distributors 106 need be mounted on the shaft 107. The other distributors 108 may be fastened on the inside of the air guide (11 in FIG. 4).

FIG. 11 shows the arrangement seen in FIG. 3 wherein a two-part housing 0., is formed with cylinder bores 1 extending parallel to the shaft 3, with the crank holes 2 extending radially therefrom. Each rotor half 200 has cores 202 (1) extending parallel to the fixed shaft 201 (3) and housing pistons'2l2. A conical sun gear 203 is formed on the fixedshaft 201 and meshes with similar bevel planet gears .204 carried on cranks 205. The motor has six such bores 202 to make it a 12- cylinder engine.

A spark distributing ring 206, an intake conduit 207, and an exhaust conduit 209 are provided at the front of the device. A fixed mounting plate 209 is provided at 210 with connections for cooling water. The points are housed at 211. g

The gear ratio is 1 to 6 between the pinion 205 and sun gear 203 so that each crank makes six revolutions for each revolution fo the cylinder housing around the fixed axis. To this end the fixed axis is provided with two sets of control passages each having three pairs of control orifices. Similarly such an engine requires three ignition coils since three cylinders will fire simultaneously rather than just two. Of course eight bores and similar changes could be made for a l6-cylinder engine.

Such engine is ideally employed for use at low speeds, and for heavy loads to prevent the rotation rate of the cranks froni growing excessively. It is similarly possible to provide an arrangement of control orifices that would, with proper doubling of ignition time, allow the engine to be operated as a two-cycle engine, in which case an oil-gas mixture could be used as fuel or fluid medium to drive it and to lubricate it. The arrangement of the pistons parallel to the axis, however permits a more powerful and longer piston stroke.

FIGS. 12-15 show a piston arrangement usable in any of the above-described motors where considerable power is to be transmitted. More specifically the crank 201' rotates to impart a stroke H to the piston 302. The crank 301 is connected via a connecting rod 303 to the piston which can assume the positions shown at 303' and 303" in FIG. 14. The piston 302 is cutaway at 305 on both sides to allow such movement and is even cut away at 304 to save weight.

A nose 306 is provided on the inside of the piston 302 and carries a piston bolt 307. The connecting rod is mounted. on the bolt 307 by means of a needle bearing 308 and on the end 310 of the crank 301' by means of a similar needle bearing 309. The piston is hollowed out at 311 to clear the rod 303 and is similarly hollowed out at 312 on its opposite end to make the piston weigh the same at both ends. Each end of the piston is formed with a circumferential groove 313 adapted to receive a pair of rings 314.

In FIGS. 16-18 there is shown an arrangement similar to that of FIG. 1 wherein the pistons all have axes A lying in a common plane orthogonal to the rotation axis A of the engine. Here again the cylinder bores carry respective pistons 404 which subdivide them into chambers 437 which are covered over by triangularsection cylinder heads 401. These heads 401 each carry a single spark plug, however, and neighboring chambers 437 are interconnected so that this is a fourcylinder engine. Each double chamber 437 is connected via a single hole 405 or 406 to the inner periphery of the housing 403. The double pistons 404 in FIG. 16 have force-transmitting arrangements 402 correthrough orifice 408a around two-thirds of its capacity of a lean mixture drawn mainly through the filter 415 and for the last third of the intake cycle draws in through orifice 407a a rich mixture of gasoline from the carburetor 414. The compression stroke follows. Ignition then takes place and makes the power stroke of the piston. The lean mixture is insufficiently rich to be exploded by the spark plug 421, but the rich mixture which lies just under this plug between the two cylinders 437 is sufficiently rich so that an explosion takes place, resulting in complete combustion with a minimum of carbon formation. Both pistons come together for the exhaust stroke to almost totally empty the cylinders; As seen in FIG. 18, in one moment in time the combined first and eight cylinders and the combined fourth and fifth cylinders ignite, while the combined second and third and combined sixth and seventh start their-compression cycles. The holes 405 are axially offset from the holes 406 to allow their respective cylin-' I ders to have overlapping intake and exhaust cycles. In-

any case chambers on diametrically opposite sides of the axis fire simultaneously to completely eliminate throw and vibration. The forces in the housing 403 equalize each other so that virtually all of the mechanicalenergy output is torque.

The engines described above produce a considerable torque while being quite small. They all run virtually sponding to the connecting-rod system shownin FIGS.

A support plate carries a carburetor 414 and its air filter and another air filter 415 so that, depending on the position of a flap valve 416 in a conduit 413 downstream of the carburetor 414, a mixture of air and some gas can be sucked in by the intake passage 407 or only air can be inspired. Another intake passage 408 is provided which will inspire a rich gas-air mixture, and the shaft 409 is further formed with an exhaust passage 412, all of the passages 407, 408, and 412 opening into different manifold grooves 411 formed on the support plate 410. In this manner a stratified mixture can be supplied to the two piston chambers 437 in order to achieve most efficient combustion and peak perform-' ance.

FIG. 18' shows the operation of the engine. The orifices 407a, 408a, and 412a on the shaft 409 can register with the openings 405 and 406 of the chambers 437. Each double cylinder 437 for one cycle first takes in vibration-free so that they wear very little. Such engines can be used in automotive vehicles to good results since they can be expanded to considerable size for any type of load. Similarly the principles described above can be applied to the manufacture of rotary motors and pumps featuring the same considerable advantages.

FIG. 19 shows an engine identical to that of FIGS. 16-18 except that it is set up as a' two-stroke or -cycle engine. More specifically the pistons 504 define chambers 537 having spark plugs 521. Each chamber 537 is, however, provided with two ports 505 and 506. The former continuously communicate with an exhaust groove 50% formed on the shaft 509, and the latter with an intake groove-509a also formed on the shaft 509 and communicating with a fan 506a which forces a gas-oil/air mixture into the chambers 537 when the pistons are near the bottom of their strokes.

Of course the holes 506 and 505 can open tangentially in'opposite directions into the chambers 537 as shown in FIG. 4 for best scavenging. The chambers 537 can also each have their own spark plugs if desired.

Such an embodiment combines extreme simplicity with a highly uniform torque output. This is due to the fact that every displacement of any piston is the result of a power stroke, the engine firing thereby sixteen times per revolution of the drive shaft.

I claim:

1.v A multiple cylinder machine comprising:

an axially extending nonrotatable axle;

an annular housing rotatable about said axle and formed with at least one chamber;

a piston reciprocable in said chamber and defining therein two independent cylinders;

first bores formed in said axle and extending axially therealong for conducting a drive medium to said cylinders;

second bores formed in said axle and extending axially therealong for conducting an exhaust medium from said cylinders; I

third bores formed in said axle and extending axially therealong for circulating a coolant therethrough, said housing being formed with passages selectively communicating between said cylinders and said first and second bores;

a nonrotatable sun gear mounted on said body;

a crankshaft having a crank connected to said piston whereby reciprocation of said piston rotates said crankshaft; and

a planet gear rotationally fixed to said crankshaft and meshing with said sun gear.

2. The machine defined in claim 1 wherein said piston is reciprocable along a piston axis defining a plane on rotation of said housing about said axle, said plane being orthogonal to the rotation axis of said housing,

said gears being spur gears. I

3. The machine defined in claim 2 wherein said piston is one of an array of such pistons each having a respective crank, crankshaft, planet gear, and piston axis, said piston axes being coplanar.

4. The machine defined in claim 3, further comprising a second such array axially spaced on said axle from the first-mentioned array and having pistons whose rotation axes lie in a second plane parallel to the firstmentioned plane of the first array.

5. The machine defined in claim 1 wherein said piston has a reciprocation axis parallel to therotation .axis

means in said body and in said housing for conducting a drive medium to and from-said cylinders;

a nonrota'table sun gear mounted on said body;

a crankshaft having a crank connected to said piston whereby reciprocation of said piston rotates said cranksahft; and

a planet gear rotationally fixed to said crankshaft and meshing with said sun gear, said piston being formed with a groove transverse to its reciprocation axis, said crank riding in said groove.

8. The machine defined in claim 7 wherein said crank is provided with a roller engaging in said groove.

, cranks, crankshafts, planet gears, and reciprocation axes arrayed about the rotation axis of said housing with said reciprocation axes lying in a common plane orthogonal to said rotation axis, each chamber communicating with the adjacent chamber of the adjacent piston, said gears being arranged to reciprocally displace adjacent pistons in opposite directions on rotation of said housing.

12. The machine defined in claim 1 wherein said passages and bores include at least one exhaust passage and bore, and two independent inlet bores with respective independent bores, said machine further comprising means for feeding a rich gas-air mixture to one of said inlet bores and a less rich gas-air mixture to the other inlet bore, said gas-air mixtures being combustible fluids constituting said fluid medium, whereby said machine has stratified carburation. 

1. A multiple cylinder machine comprising: an axially extending nonrotatable axle; an annular housing rotatable about said axle and formed with at least one chamber; a piston reciprocable in said chamber and defining therein two independent cylinders; first bores formed in said axle and extending axially therealong for conducting a drive medium to said cylinders; second bores formed in said axle and extending axially therealong for conducting an exhaust medium from said cylinders; third bores formed in said axle and extending axially therealong for circulating a coolant therethrough, said housing being formed with passages selectively communicating between said cylinders and said first and second bores; a nonrotatable sun gear mounted on said body; a crankshaft having a crank connected to said piston whereby reciprocation of said piston rotates said crankshaft; and a planet gear rotationally fixed to said crankshaft and meshing with said sun gear.
 2. The machine defined in claim 1 wherein said piston is reciprocable along a piston axis defining a plane on rotation of said housing about said axle, said plane being orthogonal to the rotation axis of said housing, said gears being spur gears.
 3. The machine defined in claim 2 wherein said piston is one of an array of such pistons each having a respective crank, crankshaft, planet gear, and piston axis, said piston axes being coplanar.
 4. The machine defined in claim 3, further comprising a second such array axially spaced on said axle from the first-mentioned array and having pistons whose rotation axes lie in a second plane parallel to the first-mentioned plane of the first array.
 5. The machine defined in claim 1 wherein said piston has a reciprocation axis parallel to the rotation axis of said housing, said gears being bevel gears.
 6. The machine defined in claim 5 wherein said piston is part of an array of such pistons having respective cranks, crankshafts, planet gears, and reciprocation axes, said reciprocation axes being parallel to and equispaced around said rotation axis of said housing.
 7. A multiple cylinder machine comprising: a nonrotatable body; a housing rotatable about said body and formed with at least one chamber; a piston reciprocable in said chamber and defining therein two independent cylinders; means in said body and in said housing for conducting a drive medium to and from said cylinders; a nonrotatable sun gear mounted on said body; a crankshaft having a crank connected to said piston whereby reciprocation of said piston rotates said cranksahft; and a planet gear rotationally fixed to said crankshaft and meshing with said sun gear, said piston being formed with a groove transverse to its reciprocation axis, said crank riding in said groove.
 8. The machine defined in claim 7 wherein said crank is provided with a roller engaging in said groove.
 9. The machine defined in claim 8 wherein said roller is one of a pair of rollers, said groove having a pair of hardened linings each engaging a respective one of said rollers.
 10. The machine defined in claim 1, further comprising a piston rod having one end pivoted on said crank and another end pivoted on said piston.
 11. The machine defined in claim 1 wherein said piston is one of at least four pistons having respective cranks, crankshafts, planet gears, and reciprocation axes arrayed about the rotation axis of said housing with said reciprocation axes lying in a common plane orthogonal to said rotation axis, each chamber communicating with the adjacent chamber of the adjacent piston, said gears being arranged to reciprocally displace adjacent pistons in opposite directions on rotation of said housing.
 12. The machine defined in claim 1 wherein said passages and bores include at least one exhaust passage and bore, and two independent inlet bores with respective independent boreS, said machine further comprising means for feeding a rich gas-air mixture to one of said inlet bores and a less rich gas-air mixture to the other inlet bore, said gas-air mixtures being combustible fluids constituting said fluid medium, whereby said machine has stratified carburation. 